I don’t remember what I ate last Friday at lunch either. Did I receive nourishment from it?
Just because something isn’t memorable doesn’t mean it makes no impact. Part of what makes impact (either negative or positive) is consistent exposure, right?
The stories I hear over and again burrow their way into my subconscious. The commercials I see over and again burrow their way into my psyche producing an effect.
I wouldn’t be so quick to dismiss the power of regular exposure to sermons.
But honestly if sermons were more conversations (διελέγετο-dielegeto or “dialogue” Acts 20:7) they would likely be more effective. For the last 10 years I was part of a group of believers who approached the “sermon” as conversation.